2001 5.4 Cold Idle Speed Ramp
F150 2001 5.4 4X4 CrewCab 138,000 miles idle speed oscillates between 700 and 1100 when extremely cold while the engine warms up and then runs normally when warm. Runs for a couple of seconds at 700 rpm and then speeds up to 900-1100 rpm for a couple of seconds and then back to 700 rpm for a couple of seconds.
Purchase OBD2 device
Found defective thermostat, changed thermostat
Engine P-0171 and P-0174, fuel pressure 30-40, changed fuel filter resolved codes.
Cleaned mass air flow sensor.